Rear wheel. Because the cassette is so wide, the drive-side spokes are almost vertical and don't provide much lateral stiffness, so they move the spoke holes towards the non-drive side to increase lateral stiffness, and it also evens out the spoke tension. Non-drive side spokes are normally at a lower tension and are more likely to fail from fatigue. Other solutions are to run less spokes or radial spoking or thinner spokes on the non-drive side.

so that means, the 'spokes' on the drive-side will have different length then those on the other side? wouldn't that means instead of shaped like a perfectly symetrical flying saucer (seen from a side) with the rim being in the centre (symetric), it shaped *sort of* like an umbrella?

sorry but it still beyond my comprehension how that shape can be useful as a bicycle wheel....

twizzle wrote:Rear wheel. Because the cassette is so wide, the drive-side spokes are almost vertical and don't provide much lateral stiffness, so they move the spoke holes towards the non-drive side to increase lateral stiffness, and it also evens out the spoke tension. Non-drive side spokes are normally at a lower tension and are more likely to fail from fatigue. Other solutions are to run less spokes or radial spoking or thinner spokes on the non-drive side.

The drive side and non-drive side spokes are actually the same length (302mm). I presume Shimano builds the left and right hub flanges to ensure the spoke lengths are equal. Probably reduces costs as well.